Well you have options.
For example Chest / Triceps.
Then for others you have choices.
Back / Biceps
Legs / Shoulders
Or Back / Shoulders
Legs / Biceps
I heard one time, that supposedly Leg training with Biceps works well, as Leg training releases more GH, which will benefit Biceps. Can't attest to the accuracy of that, although I do like the plausibility of it.
However there is also another away of looking at it, which is to train Chest, Back, Shoulders, Biceps, Triceps, then have another workout solely consisting of Legs.
In itself it is a split method, and has it's merits. You do have to make sure if you do that though espeically on Upper Body, you choose exercises wisely, otherwise your workouts will be so long you'll probably need 3 hours. Not wise.
So you'd be doing things like Bent over Barbell Rows, Close Grip Bench Press, Military Press, T-bar Rows, Push-ups, Chin-ups Power Cleans, Deadlifts, etc etc, that will give you greater combined stimulus, and less isolation, because quite a bit of Isolation stuff isn't worth it, particularly on something like a Forearm.